| Part One Comparison of Auditory Brain Stem Responses Evoked by Platform and Non-platform Tone Bursts for ChildrenObjective:To compare the correlation of thresholds between the platform and non-platform tone burst evoked auditory brainstem response (ABR) for children, select a more optimal stimulus frequency specific ABR signal.Methods:To records click, platform and non-platform tone burst ABR threshold of children aged 0-4, utilize SmartEP auditory evoked potential instrument (USA, IHS), a total of 26 patients (17 male /9 female),41 ears.Results:For 25 ears which could be evoked the threshold, the ABR threshold evoked by platform tone burst were 59.8±23. 1,57.8±23. 1,51.8±24.9,18.0±29.0 dB nHL at 0.5 kHz,1.0 kHz,2.0 kHz,4.0 kHz; the ABR threshold evoked by non-platform tone burst were 54.8±22.9,48.4±22.1,43.6±25.4,42.0±27.0 dB nHL at 0.5 kHz,1.0 kHz,2.0 kHz,4.0 kHz. The linear correlation coefficients between platform tone burst ABR threshold and non-platform tone burst ABR thresholds were 0.949,0.968,0.979 and 0.936 at each frequency, the threshold of the former were 5.0±7.6,9.4±5.8,8.2±5.2 and 7.6±10.3 dB higher than those of the latter at each frequency, the difference was significant (t values were 3.397,8.060,7.915 and 3.682, P<0.01). The ABR threshold evoked by platform tone burst was more than those evoked by non-platform at each frequency in the profound hearing loss ears.Conclusion:In our laboratory, when we use SmartEP auditory evoked potential instrument to assessment the hearing of children who wasn't profound hearing loss. ABR evoked by non-platform tone burst was better than ABR evoked by platform tone burst. But, with our instrument, the platform tone burst could apply higher intensity of stimulus, and the platform tone burst ABR could assessment the hearing of children with profound hearing loss.Part Two Comparison of Auditory Brainstem Responses Evoked by Tone Burst with Different Filter Settings for InfantsObjective:To compare the relationship of thresholds between the filter settings of 30-1500Hz and 30-3000Hz auditory brainstem response (ABR) evoked by tone burst at each frequency, sum up the characteristics of ABR threshold with two filter settings and the effect to the waveform judgement, judge the difference of the filter settings effect to ABR thresholds between two age groups. Select a more optimal frequency specific ABR test parameter. Methods:To records thresholds of click, tone burst ABR with 30-1500Hz and 30-3000Hz filter settings for infants aged 0-3, utilize SmartEP auditory evoked potential instrument (USA, IHS), a total of 18 patients (8 male/ 10 female),22 ears. Results:The thresholds of tone burst ABR with 30-3000Hz filter settings were 2.7±5.7,1.8±5.0,2.5±5.3,0.7±4.4 dB higher than those with 30-1500Hz filter settings at 0.5 kHz,1.0 kHz,2.0 kHz,4.0 kHz. The difference was significant for 0.5 kHz and 2.0 kHz (t values were 2.238 and 2.217, P<0.05), There were no significant difference between the thresholds of tone burst ABR with two filter settings at the other two frequencys. When grouped by age, there was no statistical difference between the two groups (less than 6 months group and more than 6 months group) for the difference of tone burst ABR threshold with 30-1500 Hz and 30-3000 Hz filter settings at each frequency. There was no obvious difference in amplitude between two filter settings. The waveform of ABR with filter settings of 30-1500 Hz was smoother than it with filter settings of 30-3000 Hz at the same stimulus intensity. Response curve of the latter appears jagged small interfering wave, and it was disadvantage to the judgement of thresholds. Conclusion:In our laboratory, when we use SmartEP auditory evoked potential instrument to assessment hearing of infants, tone burst ABR with 30-1500Hz filter settings is better than it with 30-3000Hz filter settings in the middle-low frequency.30-1500Hz filter settings can be used as a more optimal parameters of frequency specificity ABR to improve the accuracy of hearing assessment for infants.Part Three Effect of Auditory Brain Stem Responses Evoked by Tone Burst with Different Electroed Placed for InfantsObjective:To compare the relationship of thresholds between the tone burst evoked auditory brainstem response (ABR) with the recording electrode placed at the vertex and hairline-forehead at each frequency, sum up the characteristics of ABR threshold with two tlectrode placed and the effect to the waveform judgement, judge the (?) of the recording electrode placed effect to ABR threshold between two age groups. Select a more optimal frequency specific ABR test parameter. Methods:To records threshold of click, tone burst ABR with recording electrode placed at the vertex and hairline-forehead for infants aged 0-3, utilize SmartEP auditory evoked potential instrument (USA, IHS), a total of 15 patients (10 male/5 female), 23 ears. Results:The threshold of tone burst ABR with recording electrode placed at hairline-forehead were 2.8±5.2,2.2±4.7,3.9±4.5,3.9±4.0 dB higher than it with recording electrode placed at vertex at 0.5 kHz,1.0 kHz,2.0 kHz and 4.0 kHz. The differences were statistically significant (t values were 2.614,2.206,4.159,4.720, P values<0.05). When grouped by age, there was no statistical difference between the two groups (less than 6 months group and more than 6 months group) for the difference of tone burst ABR threshold with recording electrode placed at vertex and hairline-forehead at each frequency. The waveform amplitude of tb-ABR with recording electrode placed at vertex was much higher than it with recording electrode placed at hairline-forehead at the same stimulus intensity. It was beneficial to judge wave V at intensity around the threshold. Conclusion: The threshold and waveform of tone burst ABR with the recording electrode placed at the vertex was more optimal than it with the recording electrode placed at the hairline-forehead, and can provide better consequence of the tone burst ABR.Part Four Effect of Auditory Brainstem Response Evoked by Tone Burst While Both the Electrode Placed and Filter Setting Changed for InfantsObjective This study is to compare the diffrence between the thresholds of tone burst ABR with two (? record parameters at each frequency for infants. One record (?) is that the recording electrode placed at the vertex and the 30-1500 (?) setting (The first set of record parameters for short). Another record parameter is that the recording electrode placed at the hairline-forehead and the 30-3000 Hz filter setting (The second set of record parameters for short). To sum up the characteristics of ABR threshold with the two record parameters and the effect of the waveform judgement, select a more optimal test condition of frequency specific ABR. Methods To records click, tone burst ABR threshold with the two record parameters as mentioned earlier in children aged 0-6months, a total of 12 patients (10 male/2 female),20 ears. Other parameters were the same. Results The threshold of tone burst ABR with the recording electrode placed at the hairline-forehead and the 30-3000 Hz filter setting was 7.0±5.5,7.3±6.0,7.3±4.7,8.0±5.5 dB higher than it with the recording electrode placed at the vertex and the 30-1500 Hz filter setting for at 0.5kHz,1.0 kHz,2.0 kHz and 4.0 kHz. The difference was significant for each frequency (t values were 5.715,5.445,6.866 and 6.532, P＜0.01). There was obvious difference between the two amplitudes of tb-ABR with difference record parameters. The amplitude of tone burst ABR with the first set of record parameters was higher than it with the second set of record parameters. The waveform of ABR with the former settings was smoother than it with the latter at the same stimulus intensity, and it was more easy to recognize the wave V. Conclusions The threshold and waveform of tone burst ABR with the recording electrode placed at the vertex and the 30-1500 Hz filter setting was more optimal than it with the recording electrode placed at the hairline-forehead and the 30-3000 Hz filter setting, the former could be used as a more optimal record parameters of ABR, and can provide better consequence of the threshold test.
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